Some embodiments are directed to a compensated and compact pressure regulator for the distribution of fluid under pressure and a tank head incorporating the pressure regulator.
The technical sector of some embodiments is the field of the production and the use of expansion devices for fluid under pressure, such as gases, in which the aim is for the delivery of the fluid under pressure expanded to a determined pressure to be independent of the pressure of the fluid under pressure at the inlet.
In order to produce the expansion of a fluid under pressure, from a first high pressure level to a second low pressure level, lower than the high pressure, it is in fact known to one of ordinary skill in the art to use expansion devices, more simply called pressure regulators.
Related art pressure regulators operate based on the equality of two forces exerted directly or indirectly, on either side of a mobile regulation piece such as a membrane or a piston, through, on the one hand, the fluid at the high pressure and at the low pressure, and on the other hand an element with expansion or compensation spring effect; thus, in the most commonplace case where the reference force of the spring element is exerted on the side opposite to that transmitted both by the fluid at the low pressure and at the high pressure, this fluid fills two chambers under two different pressures, separated by a partition provided with a duct in which slides a rod integral to the mobile regulation piece and including a valve which can close this duct in the direction from the high-pressure chamber to the low-pressure chamber. When the force transmitted both by the fluid at the low pressure and at the high pressure is weaker than the opposing one transmitted by the spring, the latter pushes the mobile regulation piece whose valve is situated on its rod then opens the intake for the fluid under high pressure: the latter will thus supply the chamber at the low pressure until the latter, by increasing, makes it possible to exert a force on the mobile regulation piece that is equal to, then greater than, the opposing force of the spring element; this greater force will push the mobile regulation piece until the intake for the fluid under high pressure is closed, and so on; the balance of the forces thus ensures the delivery of a fluid at a quasi-constant desired low pressure for a determined thrust value of the spring element, which can be adjustable.
However, in most of the related art pressure regulators, if the high pressure of the fluid to be expanded undergoes great variations, the corresponding force on the mobile regulation piece will change and the opening of the valve will no longer occur at the same moment, resulting in a variation of the low pressure of the expanded fluid through the valve and therefore a poor operation and efficiency, and disturbances in the user apparatus, which is situated downstream of the pressure regulator from which it directly receives the fluid at the low pressure.
Each pressure regulator thus has a “dynamic expansion curve” which is representative of this property which can therefore be very detrimental. To mitigate this drawback, several categories of related art pressure regulators have been developed with the objective, more or less well achieved, of delivering an outlet pressure independently of the inlet pressure when the latter can vary, such as:                those with two stages,        those, of conventional type, additionally having a “compensated” valve which cancels the influence of the high pressure but to the detriment of simplicity and the compactness of the pressure regulator, and        those, the to be of inverted type, being designed in such a way that the high pressure, bearing circularly and on a surface at right angles to the direction of displacement, generates on the mobile regulation piece a quasi-zero force compared to those exerted both by the spring element which bears in the direction of opening of the valve and the opposing force exerted by the fluid at the low pressure on the surface of the mobile piece and which tends to close the valve, as described in the patent applications EP362166, FR2879721 and FR2050407.        